The normal mode of operation of a Telephone Answering Device (TAD) is as follows:
After a predetermined number of rings, sensed by a ring detection circuit, the TAD goes off-hook and broadcasts an outgoing message that had been prerecorded on an announcement tape. After the end of the playing of the announcement tape a recording means, typically a tape cassette, is activated to record an incoming message from the calling party. The recording can be ended either by limiting the permitted recording time or automatically upon the caller hanging up. The TAD recognizes that the calling party has hung up by one of two automatic termination methods: